import java.math.BigInteger;
import java.util.ArrayList;
import java.util.List;

/**
 * Created by Administrator on 2014/12/15.
 */
public class Problem8 {
    public static void main(String[] args) {
        BigInteger integer = new BigInteger(
                "73167176531330624919225119674426574742355349194934" +
                "96983520312774506326239578318016984801869478851843" +
                "85861560789112949495459501737958331952853208805511" +
                "12540698747158523863050715693290963295227443043557" +
                "66896648950445244523161731856403098711121722383113" +
                "62229893423380308135336276614282806444486645238749" +
                "30358907296290491560440772390713810515859307960866" +
                "70172427121883998797908792274921901699720888093776" +
                "65727333001053367881220235421809751254540594752243" +
                "52584907711670556013604839586446706324415722155397" +
                "53697817977846174064955149290862569321978468622482" +
                "83972241375657056057490261407972968652414535100474" +
                "82166370484403199890008895243450658541227588666881" +
                "16427171479924442928230863465674813919123162824586" +
                "17866458359124566529476545682848912883142607690042" +
                "24219022671055626321111109370544217506941658960408" +
                "07198403850962455444362981230987879927244284909188" +
                "84580156166097919133875499200524063689912560717606" +
                "05886116467109405077541002256983155200055935729725" +
                "71636269561882670428252483600823257530420752963450");
        String string = integer.toString();
        List<BigInteger> list = new ArrayList<>();
        for (int i = 0; i < string.length() - 13; i++) {
            String substring = string.substring(i, i + 13);
            BigInteger count = new BigInteger("1");
            for (int j = 0; j < substring.length(); j++) {
                count = count.multiply(new BigInteger(substring.substring(j,j+1)));
            }
            list.add(count);
        }
        BigInteger result = list.stream().max((x,y) -> x.compareTo(y)).get();
        System.out.println(result);
    }
}
